Scaling law for noise variance and spatial resolution in differential phase contrast computed tomography

Authors


Abstract

Purpose:

The noise variance versus spatial resolution relationship in differential phase contrast (DPC) projection imaging and computed tomography (CT) are derived and compared to conventional absorption-based x-ray projection imaging and CT.

Methods:

The scaling law for DPC-CT is theoretically derived and subsequently validated with phantom results from an experimental Talbot–Lau interferometer system.

Results:

For the DPC imaging method, the noise variance in the differential projection images follows the same inverse-square law with spatial resolution as in conventional absorption-based x-ray imaging projections. However, both in theory and experimental results, in DPC-CT the noise variance scales with spatial resolution following an inverse linear relationship with fixed slice thickness.

Conclusions:

The scaling law in DPC-CT implies a lesser noise, and therefore dose, penalty for moving to higher spatial resolutions when compared to conventional absorption-based CT in order to maintain the same contrast-to-noise ratio.

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